Jury is still out on spider x spider, some say they have smaller clutches because spider x spider fails to fertilize and get reabsorbed. Some say they they see no difference in clutch size. IF there is any effect as a super form, it's VERY subtle, enough that even after years of pairings no one's really certain.
As far as the original question goes, reptiles are more resilient to line breeding than mammals. Most of these morphs started off as dinkers, they have to be line bred to prove them out. Personally I have no problem with 2 generations (or 3 if I was on a very special project), but after that I'd try to bring in outside blood.
Can you please explain how the part in bold works?
Seeing that follicles don't met the males sperm until ovulation after which time it is impossible for a female to reabsorb.